Decorator crab

[maiceman]

I bought a couple of large pieces of LR at the LFS about 3 weeks ago. What I didin't know was that I got a little bonus (so to speak) in the deal. I found this bonus 2 days ago as it was trying to destroy my green button polyps. I could see that it was some kind of crab but did not look anything like my algae eating hermit crabs. Then I noticed some different types of growth on it's shell that I had been admiring just the night before..... pretty good camo on this critter. I have identified it as a decorator crab. Well needless to say he is no longer in my tank and my corals and other crabs are safe from this carnivore now. I also noticed that my hermit crabs are much more active again except that 1 is missing... I think he was a midnight snack. Just a warning for those of you buying LR.. you never know what else you may be getting.

[michealprater]

I wouldnt call a decorator crab a carnivore. they dont accually eat corals (or meat for that matter). They just use peices of coral for discuise.

[maiceman]

Well, here is the description from Dr. Fosters & Smiths web site.

"The Spider Decorator Crab, also known as Camposcia Decorator Crab or Decorator Crab, is a member of the Majidae family of spider and decorator crabs. It decorates its brown body with sponges, shells, rocks, and other items as a method of camouflage.

It is nocturnal, hunting at night. It is not reef compatible, eating some invertebrates. It may be harmful, as well, as it harvests algae, soft corals, and invertebrates to adorn its shell.

The diet of the Spider Decorator Crab should include meaty foods such as chopped fish and clams.

Approximate Purchase Size: 1-1/2" to 3"

By saying that they hunt and eat some invertebrates I guess I jumped to saying it was a carnivore...I may be wrong.... he is an invertivore. But they do suggest feeding them meaty foods & chopped fish and I think that is the definition of carnivore.

[maiceman]

Changes since I removed the decorator crab are evident now. The number of worm trails in my DSB has tripled. The small snails in the clean up crew are reproducing like crazy. My Hermit crabs are not hiding under the LR anymore. My astria snails are not hanging out up on the glass exclusively, and my green button polyps are much more extended and healthy looking.